That's odd, I use salifert and always get an accurate reading with all their tests. Is it out of date by chance? The date should be on the top of the box.

Also, I don't have their ammonia test, could you be missing a step? Their tests can be a bit cumbersome and confusing. lol

Not sure. It's only one solution that you add .5 then add the other .5 I had one that was out of date. So I thought that was the problem but this new test kit is doing the same thing. Guess I will stick with the API.